Can Food Affect Your Mood?

An Apple A Day Keeps The Blues Away

Author: Dr. Stephen Chaney

Can food affect your mood? In rural North Carolina you still occasionally see bumper stickers that say “Life Happens”. Of course, the word they use isn’t exactly “Life”, but you get the point.

We can’t always control what happens to us. What is important is how we react when bad things happen to us. Do we brush them off and move on, or do we let them get us down? There is no shortage of experts telling us how we can keep the blues away. We are told to count our blessings, meditate, think happy thoughts, develop support groups – the list goes on and on.

But is there perhaps one important parameter that most of these experts are missing? Could the foods we eat make us blue?

The standard American diet (S.A.D.) is high in processed foods, fat (especially saturated and trans fats), refined grains, simple sugars, salt and calories. As I’ve said before, almost anything would be better.

You probably already know that the S.A.D. leads to obesity and a whole host of diseases – including heart disease, cancer and diabetes – just to name a few. But did you know that the S.A.D. could make you sad? That’s what two recent studies suggest.

Can Foods Affect Your Mood? Does Junk Food Make You Sad?

The first study by Akbaralay et al (British Journal of Psychiatry, 195: 408-413, 2009) looked at the dietary patterns and mental health outcomes of 3486 participants in the Whitehall II Prospective Study.

In case you didn’t know it, Whitehall is the central district in London where most of the British government offices are located. So the 3486 participants in this study were bureaucrats. They were middle aged (average age 55.6 years old) office staff (74% men, 26% women) who spent most of their day sitting and really didn’t like their jobs very much. (I made up the part about not liking their jobs. It is hard to imagine that kind of job would be deeply fulfilling, but I’m sure that some of the bureaucrats liked their jobs better than others – which is the whole point of this study.)

At the beginning of the study the participants were given a 127 item food frequency quiz to fill out. Interestingly enough, the food preferences of the participants in this study clustered neatly into two groups.

The diets of the processed foods groups predominantly consisted of sweetened desserts, chocolates, fried foods, processed meats, refined grains and high fat dairy products. In short the diet of this group was pretty similar to what we think of as the Standard American Diet (S.A.D.). In contrast, the diets of the whole foods group consisted mostly of vegetables, fruits, fish and whole grains.

Five years later the study participants were analyzed for depression using a 20 item standardized depression scale.

The results were pretty eye-catching. The processed food group was 58% more likely to suffer from depression than the whole food group! And this was after correction for age, gender, weight, marital status, education, employment grade, physical activity, smoking and diseases (high blood pressure, heart disease, diabetes, and stroke).

The reasons for this astounding correlation between diet and depression are not clear. Can food affect your mood? Does this give us more insight?

The authors speculated that the diets of the whole food group were likely higher in antioxidants, folic acid and omega-3 fatty acids than the diets of the processed food group – and studies have suggested that each of these nutrients may protect against depression.

The authors also suggested that it might be an indirect effect. Diets that are high in saturated fats and refined grains and low in omega-3 fatty acids increase inflammation, and studies have suggested that inflammation can lead to depression.

Can Food Affect Your Mood? Does Healthy Food Make You Glad?

The previous study suggested that junk food may make you sad. So you might be asking: “Does that mean that healthy foods can make you glad?” According to one recent study (Br J Health Psychol, Jan 24, 2013, doi: 10.1111/bjhp.12021) the answer may be yes.

A team from the University of Otago in New Zealand enrolled 281 young adults (average age = 20) in a study that looked at the effect of diet on their mood. Each day for 21 consecutive days they recorded their mood and what foods they ate using an online questionnaire. In particular, they reported the number of servings of fresh fruit and vegetables and of several unhealthy foods such as biscuits or cookies, potato chips or French fries and cakes or muffins.

The investigators correlated the foods eaten with the moods reported by the participants on the same day, and again on the day after those foods were eaten. Once again, the results were pretty impressive.

On the days when people ate more fruits and vegetables they reported feeling calmer, happier and more energetic than they did on other days (p = .002 – anything less than .05 is considered a statistically significant difference). And the good effects of fruit and vegetable consumption carried over to the next day as well (p < .001).

Can food affect your mood? While I paraphrased the “apple a day” quote to introduce this study, one apple won’t quite do it. According to this study it takes about 7-8 servings of fruits and vegetables to positively affect mood. In addition, it probably wasn’t just the fruits and vegetables that made the difference. Based on the previous study I would guess that the participants in the study may have eaten other healthy foods such as whole grains and fish on their good days.

Can Food Affect Your Mood?

Taken together these two studies suggest that the next time you feel a little blue you may want to look at your diet. You may want to include a healthier diet along with the meditation and positive thinking.

Of course, these studies both measured correlations between diet and mood, and any good scientist will tell you that correlations do not prove cause and effect. It could be that when people are “down in the dumps” they just naturally reach for junk foods rather than fruits and vegetables.

However, since there is no downside to consuming fruits and vegetables, I feel fully comfortable recommending more fruits and vegetables in our diets. If their health benefits aren’t enough to motivate you, maybe the possibility of improving your mood will!

There are some things you just can’t control. To paraphrase those country songs, you can’t keep your girl and dog from running off. Life happens to all of us. Can food affect your mood? If you want to keep your mood where it should be, you can always reach for those fresh fruits and vegetables, whole grains and sources of omega-3 fatty acids.

The Bottom Line

Two recent studies have suggested what we eat can affect our mood.

The first study showed that people who habitually consumed a diet consisting of sweetened desserts, chocolates, fried foods, processed meats, refined grains and high fat dairy products were 58% more likely to suffer from depression than people who habitually consumed a diet consisting mostly of vegetables, fruits, fish and whole grains.

The second study showed that the subjects in their study reported feeling calmer, happier and more energetic on the days when they ate more fruits and vegetables than they did on the days they ate junk foods.

Of course, these studies both measured correlations between diet and mood, and any good scientist will tell you that correlations do not prove cause and effect. It could be that when people are “down in the dumps” they just naturally reach for junk foods rather than fruits and vegetables.

However, since there is no downside to consuming a healthier diet, I feel fully comfortable recommending more fruits and vegetables, whole grains and omega-3s in our diets. If their health benefits aren’t enough to motivate you, maybe the possibility of their improving your mood will!

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

Traditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

How good was the study?

What were its limitations?

Are the claims justified?

How Was The Study Designed?

The investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.

The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.

The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

The weight maintenance portion of the study lasted 5 months – much longer than any previous study.

All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.

The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.

Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

Do Low-Carb Diets Help Maintain Weight Loss?

The results were striking:

The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.

These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.

These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

What Are The Pros And Cons Of This Study?

This was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.

Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.

The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

What Does This Study Mean For You?

This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.

In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.

The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.

This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.

However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.

In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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